Last week T&E released infrared images of methane slip in the exhaust plumes of gas-powered ships at Rotterdam. Image Credit: T&E
Gas-powered shipping advocates SEA-LNG have claimed 'misinformation' over the methane slip issue risks delaying maritime decarbonisation, in the latest sally of the ongoing war of words over LNG as a bunker fuel.
"SEA-LNG is disappointed to see the ongoing campaign of misinformation that misrepresents the progress the industry has made, and is continuing to make, to reduce slip," SEA-LNG said in an emailed statement on Thursday.
"Sensationalist claims lacking scientific evidence are a transparent attempt to distract the industry from investing in LNG – a solution that can deliver immediate greenhouse gas emissions reductions and provide a low-risk, incremental pathway for full decarbonisation of the maritime sector."
The comments came in response to a press release published last week by NGO Transport and Environment showing independently verified infrared images of methane slip in the exhaust plumes of gas-powered ships at Rotterdam in November.
The impact of methane slip varies hugely depending on whether the analysis takes a 20- or 100-year view of the greenhouse effect of its presence in the atmosphere
Methane slip is the unintended release of unburned natural gas from LNG during its storage, transportation and use. The greenhouse effect from methane in the atmosphere is much stronger than that of CO2, meaning methane slip significantly reduces the environmental benefits of switching from conventional bunker fuels to LNG.
Methane slip is a well-known consequence of burning gas in marine engines and has been long acknowledged by both sides of the debate. Where they differ is what the impact is of those emissions.
T&E cited IMO data estimating that 0.2-3% of methane slips from the combustion process from LNG-fuelled ships into the atmosphere. However, is did not say if its latest research showed if the methane slip from the ships in Rotterdam was more or less than expected.
"Getting exact numbers on the amount of methane was beyond us at this stage, due to the challenge of getting close enough to the ships," a spokesperson from T&E told Ship & Bunker.
Overall, T&E says "about 80% of LNG today is burned in an engine with worse total greenhouse gas emissions than traditional engines" burning oil bunkers.
SEA-LNG and fellow LNG bunker advocates Society for Gas as a Marine Fuel (SGMF) say there is a well-to-wake GHG emissions reduction compared to VLSFO-fuelled equivalent ships of 14-23% for two-stroke slow-speed engines, and 6-14% for four-stroke medium-speed engines
Measuring GHG Impact
The impact of methane slip varies hugely depending on whether the analysis takes a 20- or 100-year view of the greenhouse effect of its presence in the atmosphere. Supporters and opponents of LNG bunkers favour the use of the respective analytical model that makes their case look strongest, and no compromise has emerged between the two.
"In promoting LNG ships, European policymakers are locking us into a future of fossil gas," Delphine Gozillon, shipping officer at T&E, said in the statement.
"The ships may be painted green, but, beneath the surface, the truth is that most LNG ships on the market today are more damaging for the climate than the fossil ships they're supposed to replace."
all LNG-fuelled engines have minimal levels of methane slip by 2030, if not sooner
SEA-LNG sees the methane slip issue being gradually resolved as technology develops.
"With the ongoing steady technological advancements, the GHG benefits will only improve in the future versions of LNG-fuelled engines as the technologies are more widely adopted by the shipping sector," the organisation said in Thursday's statement.
"It is important to recognise that methane slip represents a waste of precious energy.
"Engine manufacturers are commercially incentivised to reduce slip to improve overall efficiency and performance.
"LNG-fuelled engines are available now which have minimal levels of slip: these engines represent at least half the LNG new build order book.
"For those technologies for which slip remains an issue, levels have fallen four-fold since the early 2000s and engine manufacturers continue to identify technological pathways that will mean all LNG-fuelled engines have minimal levels of methane slip by 2030, if not sooner."